Well-being of people, including income, health and happiness.
Social development is…
The level of access to services and the wellbeing of people (e.g. Healthcare and Education).
Environmental development is…
The quality of the built and natural environment. (E.g. Access to safe water and Waste management).
Political development is…
The stability of the government (how effectively the country is run) and the freedom and rights of the people who live there. (E.g. Freedom of speech and corruption levels).